The invention relates to a smart card with a card carrier on which a data processing circuit and also a connection assembly for the contactless communication of data between the data processing circuit and an external data processing station are provided.
A generic smart card and an external data processing station form a data system that is used for counting cashless purchases, for monitoring passenger traffic or for simple charge management in the context of access to a telephone network. For such purposes, a user acquires a smart card on which a data processing circuit containing a microprocessor is provided. For the communication of data between the data processing circuit and the external data processing station, an alternating field generated by the external data processing station is modulated by the smart card in the case of contactless transmission methods. In this case, by way of example, a smart card coil provided in the connection assembly is subjected to a capacitive or resistive load in a varying manner over time, with the result that its electromagnetic properties alter. This has a reaction upon a station coil in the external data processing station. From the reaction, it is possible to draw conclusions about data stored in the data processing circuit.
The generic smart card is constructed as a plastic card large enough to be stowed securely in a purse, for example. In the course of producing the generic smart card, first of all an integrated circuit is applied to a card carrier made of plastic. Afterwards, a transmitting/receiving coil connected to corresponding terminals of the integrated circuit is applied along the outer edges of the smart card. Such a smart card is disclosed for example in Published, Non-Prosecuted German Patent Application DE 44 10 732 A1. In the case of the generic smart card, the fact that production is complicated and expensive is disadvantageous. If a smart card does not operate correctly, the defective smart card is destroyed.
Published, Non-Prosecuted German Patent Application DE 44 37 721 A1 shows an electronic module for incorporation into a data carrier, the electronic module has an integrated circuit which is disposed on a module carrier and is conductively connected to a coil for contactless data exchange.
It is accordingly an object of the invention to provide a smart card which overcome the above-mentioned disadvantages of the prior art methods and devices of this general type, which always operates reliably, and is produced reliably and with little outlay.
With the foregoing and other objects in view there is provided, in accordance with the invention, a smart card, containing a card carrier having a given region and at least one module carrier disposed in the given region of the card carrier. The at least one module carrier, includes a base plate; a connection assembly disposed on the base plate and having at least one transmitting/receiving coil with sections disposed in at least two different planes with respect to a main direction in which the base plate extends, the sections of the at least one transmitting/receiving coil operating in a synchronized manner with one another; and a data processing circuit. The connection assembly provides contactless communication of data between the data processing circuit and an external data processing station. In an alternative, the sections are configured such that the sections are kept in a resonance phase angle with respect to one another.
According to the invention, the data processing circuit and the connection assembly are provided in the region of at least one module carrier and the card carrier has a region for accommodating the module carrier or the module carriers.
The invention is based on the fundamental concept that the disadvantages in generic smart cards stem from the fact that only when the smart card has been completed is it possible to test whether the integrated circuit cooperates correctly with the transmitting/receiving coil. According to the invention, the parts which are essential for the functioning of the smart card, that is to say a functional assembly, are produced separately from the card carrier on the module carrier and connected to one another only during the final assembly of the card carrier and the module carrier. This makes it possible firstly to test the functional assembly in respect to its functioning. If it is established that the data processing circuit does not cooperate correctly with the connection assembly on the functional assembly, then the functional assembly can be destroyed without an inherently useful card carrier having to be destroyed as well. Furthermore, it is possible to accelerate the production of the functional assembly since the module carrier, which takes up only a small amount of space, makes it possible to provide smaller and faster production apparatuses.
According to the invention, the module carrier can be fixedly connected to the smart card, it being possible for that region which is provided on the card carrier for accommodating the module carrier also to be configured as a cutout. With a suitable configuration of the module carrier and the cutout, it is possible to ensure that a positively locking connection is already produced when the module carrier is inserted into the receptacle, the connection only having to be fixed.
A particularly advantageous smart card according to the invention is produced when the connection assembly has at least one transmitting/receiving coil which can also be disposed in two different planes with respect to the main direction in which the module carrier extends. In this case, provision is made, in particular, for a section of the transmitting/receiving coil to be disposed on a surface of the module carrier, while another section may be disposed in a layer inside of the module carrier. This can be achieved in a particularly simple manner by use of a two-layer metallization coating, a sandwich-like structure being particularly appropriate for the module carrier. In this case, the sections of the transmitting/receiving coil on the surface of the module carrier and inside the module carrier may be disposed in a plane-parallel manner, the individual sections being connected to one another by contacts. This can be achieved in a particularly simple manner by use of plated-through holes in the region of terminals of the respective transmitting/receiving coil regions. It is preferable for the individual sections of the transmitting/receiving coil to be connected in series, since this results in a transmitting/receiving coil which can influence an external alternating field with a high efficiency. In this case, a particularly high efficiency of the transmitting/receiving coil is produced when the transmission device, which is often part of the data processing circuit, is configured in such a way that the sections of the transmitting/receiving coil can be kept in a resonance phase angle with respect to one another. This can be done for example by suitably connecting in capacitances and/or inductances, this preferably being done in such a way that the resonant frequencies of the regions of the transmitting/receiving coil in each case correspond.
In a departure from this, or to supplement the above-mentioned embodiment, the transmission device may also be configured in such a way that the sections of the transmitting/receiving coil can be operated such that they are synchronized with one another. This can advantageously be done so as to result in amplification of the alternating field issuing from the transmitting/receiving coil. This is significant for active cards that emit a signal. By applying phase gating technology, it is possible to achieve synchronization of the signals in with the sections of the transmitting/receiving coil, to be precise in such a way as to result in amplification of an alternating field generated by the transmitting/receiving coil. In the case of passive cards, it is thereby possible to achieve a particularly high degree of coupling between the smart card and an external data processing station.
A further improvement in the transmission quality of data between the smart card and the external data processing station is produced when the module carrier has at least one section configured as a coil core for the transmitting/receiving coil. In this case, the module carrier may be formed from plastic into which permeable material such as ferrite, for example, is incorporated. If the permeable material is present as a multiplicity of ferrite particles, the latter are bound, for the purpose of mutual insulation, in a synthetic composition provided in the module carrier. The coil core produced in this way serves for achieving a high field amplification factor. Such a dielectric makes it possible to achieve relative magnetic permeabilities of the order of magnitude of 5,000 and thus high flux densities.
A method for producing the module carrier for the smart card configured in the manner described above has the following steps:
a. incorporating a first coil section into a plastic layer;
b. applying a second coil section to the plastic layer;
c. connecting terminal regions of the first coil section and of the second coil section to one another; and
d. applying an integrated circuit to the module carrier.
In this case, the step of connecting the terminal regions of the first coil section to the second coil section can be effected by through-plating, which can be achieved in a simple manner using known production methods.
The step of applying the integrated circuit can be effected either by a flip-chip technique or by conventional bonding techniques. In the case of the conventional bonding techniques, it is possible to have recourse to a conductive adhesive or to known solders as the bonding agent. Especially in the case of the bonding techniques, it is provided that not only the connection assembly but also the data processing circuit may optionally be covered with a hardenable covering composition, to be precise, in particular after the production of the module carrier. The covering compositions used for this purpose may be in particular thermally or UV curing.
The invention also relates to a method for producing a smart card which has the following steps:
a. providing a card carrier having a receptacle for a module carrier;
b. providing a module carrier according to the invention having a data processing circuit and a connection assembly;
c. introducing the module carrier into the receptacle; and
d. connecting the module carrier to the card carrier.
The method according to the invention enables a smart card to be produced in a particularly simple and cost-effective manner.
The above-mentioned production steps for producing the smart card according to the invention and/or the module carrier according to the invention with a double-layered transmitting/receiving coil can, of course, also be applied to the production of smart cards and/or module carriers with a single coil layer.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a smart card, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.